<!doctype html>
<meta charset="utf-8">
<title>Linear gradients for non-square elements reference</title>
<style>
.a,
.b,
.c,
.d {
  width: 200px;
  height: 100px;
}
.a {
  background: linear-gradient(-206.56505118deg, black 50%, lightgray 50%);
}
.b {
  background: linear-gradient(206.56505118deg, black 50%, lightgray 50%);
}
.c {
  background: linear-gradient(-26.56505118deg, black 50%, lightgray 50%);
}
.d {
  background: linear-gradient(26.56505118deg, black 50%, lightgray 50%);
}
</style>
<div class="a"></div>
<div class="b"></div>
<div class="c"></div>
<div class="d"></div>
